# solving systems of equations

• Oct 9th 2006, 07:13 PM
wpcp15
solving systems of equations
r + s + t=5
2r + 7s - 3t=13
1/2r - 1/3s + 2/3t=-1

I get confused when I come to the fractions.
• Oct 9th 2006, 07:18 PM
topsquark
Quote:

Originally Posted by wpcp15
r + s + t=5
2r + 7s - 3t=13
1/2r - 1/3s + 2/3t=-1

I get confused when I come to the fractions.

So get rid of them. Multiply the bottom equation by 6. The bottom equation becomes:
3r - 2s + 4t = -6

and solve the system of equations with this.

-Dan
• Oct 9th 2006, 07:19 PM
wpcp15
Thank You
• Oct 9th 2006, 07:45 PM
wpcp15
1 more question
One more question, what about?

a + b=3
-b + c=3
a +2c=10
• Oct 9th 2006, 07:59 PM
ThePerfectHacker
Quote:

Originally Posted by wpcp15
One more question, what about?

a + b=3
-b + c=3
a +2c=10

Add the first two,
a+c=6
a+2c=10
From third subtract this result,
c=4
Thus,
a=2
Thus,
b=1
• Oct 9th 2006, 09:46 PM
AfterShock
a + b = 3
-b + c = 3
a + 2c = 10

It's so easy after making it into a matrix:

1 1 0 3
0 -1 1 3
1 0 2 10

Where the last column is the augmented matrix (the = part).

Row reduce the rows:

1 0 0 2
0 1 0 1
0 0 1 4

x_1 = 2
x_2 = 1
x_3 = 4

x_1, x_2, x_3 -> a, b, c, respectively.

Try it with the first equation.